Aircraft comprise a plurality of sensors which are used for measuring various physical characteristics related to the aircraft and its operation. The sensors are typically distributed throughout the aircraft and are coupled to data lines in order to provide the sensor signals of the sensors, which sensor signals are characteristic of the various physical characteristics or measurement values, to one or more remote data collection or data processor. Each data line may be a bus line, which carries the sensor signals of more than one of the sensors, or a data line which is only associated with and coupled to one of the sensors. The data lines may carry the sensor signals in analog or digital form.
For many purposes it would be desirable to have free access to multiple ones of the measurement values and to link them together. However, the sensors typically provide their measurement values and corresponding sensor signals to a plurality of different data collection or data processing devices, and the data, although in principle available on-board the aircraft are not accessible outside the respective data collection or data processing device. Thus, for many types of aircraft all or most of the measurement values and sensor signals are not available for remote monitoring during operation or maintenance without costly and complex system redesign and upgrade.